Introduction

The External Storage Support application enables you to mount external
storage services and devices as secondary ownCloud storage devices. You
may also allow users to mount their own external storage services.

Enabling External Storage Support

Storage Configuration

To create a new external storage mount, select an available backend from
the dropdown Add storage. Each backend has different required options,
which are configured in the configuration fields.

Each backend may also accept multiple authentication methods. These are
selected with the dropdown under Authentication. Different backends
support different authentication mechanisms; some specific to the
backend, others are more generic. See external_storage/auth_mechanisms
for more detailed information.

When you select an authentication mechanism, the configuration fields
change as appropriate for the mechanism. The SFTP backend, for one
example, supports username and password, Log-in credentials, save in
session, and RSA public key.

Required fields are marked with a red border. When all required fields
are filled, the storage is automatically saved. A green dot next to the
storage row indicates the storage is ready for use. A red or yellow icon
indicates that ownCloud could not connect to the external storage, so
you need to re-check your configuration and network availability.

If there is an error on the storage, it will be marked as unavailable for ten minutes.
To re-check it, click the colored icon or reload your Admin page.

User and Group Permissions

A storage configured in a user’s Personal settings is available only to
the user that created it. A storage configured in the Admin settings is
available to all users by default, and it can be restricted to specific
users and groups in the Available for field.

Mount Options

Hover your cursor to the right of any storage configuration to expose
the settings button and trashcan. Click the trashcan to delete the
mountpoint. The settings button allows you to configure each storage
mount individually with the following options:

Encryption

Previews

Enable Sharing

Filesystem check frequency (Never, Once per direct access)

The Encryption checkbox is visible only when the Encryption app is
enabled.

Enable Sharing allows the ownCloud admin to enable or disable sharing
on individual mountpoints. When sharing is disabled the shares are
retained internally, so that you can re-enable sharing and the previous
shares become available again. Sharing is disabled by default.

Using Self-Signed Certificates

When using self-signed certificates for external storage mounts the
certificate must be imported into ownCloud.

Available storage backends

The following backends are provided by the external storages app. Other
apps may provide their own backends, which are not listed here.

A non-blocking or correctly configured SELinux setup is needed for these backends to work. Please refer to the SELinux configuration.

Allow Users to Mount External Storage

Check "Allow users to mount external storage" to allow your users
to mount storages on external services. Then enable the backends you want to allow.

Be careful with the choices that you enable, as it allows a user to make potentially arbitrary
connections to other services on your network!

Setting Up Google Drive and Dropbox Connections

When an external storage is created which uses either Google Drive or Dropbox, a link to the
respective configuration page is available, next to the service name.

In the screenshot above, you can see that two external storage
connections have been created, but not configured. One goes to Google
Drive, the other to Dropbox. If you click the cog icon next to the name
of either, the respective app configuration page will open in a new tab,
or a new window. From there, you can manage the configuration and obtain
the respective credentials needed for configuring the connection.

Detecting Files Added to External Storages

You cannot scan/detect changed files on external storage mounts when you select the
Log-in credentials, save in session authentication mechanism. However, there is a workaround,
and that is to use Ajax cron mode.
See Password-based Mechanisms for more information.

ownCloud may not always be able to find out what has been changed remotely
(files changed without going through ownCloud), especially when it’s very deep
in the folder hierarchy of the external storage.

You might need to setup a cron job that runs sudo -u www-data php occ files:scan --all.
Alternatively, replace –all with the user name to trigger a rescan of the user’s files periodically,
for example every 15 minutes, which includes the mounted external storage.